We plan to utilize our in vitro reconstitution system to define the functions and interrelationships of the 3 nucleocapsid proteins of vesicular stomatitis virus during transcription. Since transcription and replication are apparently interrelated, these studies will form the foundation for projected studies on how RNA replication occurs at the molecular level. Various ts mutants from different complementation groups will be characterized to determine which of the three nucleocapsid proteins contains the ts lesion in each group. BIBLIOGRAPHIC REFERENCES: Emerson, Suzanne U. 1975. Vesicular stomatitis virus: structure and function of virion components (review article), in press. Current topics in Microbiology and Immunology. Emerson, Suzanne U. and Yu-Hwa Yu. 1975. Both NS and L proteins are required for in vitro RNA synthesis by vesicular stomatitis virus. J. Virol. 15: 1348-1356.